1. Field of the Invention
The invention relates to a method for the production of a dental prosthetic item, in which method the dental prosthetic item is machined manually.
The invention further relates to a method for the production of a dental prosthetic item comprising a framework and a superstructure.
Furthermore, the invention relates to devices for partial manual machining of a dental prosthetic item.
2. Prior Art
Methods are known in the prior art, in which dental prosthetic items are produced using computer-aided design and production techniques to various extents.
The older prior methods dispense entirely with the use of computers. In most cases, an impression of the dental situation is made both of the jaw that requires treatment and of the opposing jaw. This impression is used as the basis for the production of a positive model, on which a dental technician will produce the dental prosthetic items in several layers. Initially, a high-strength framework is produced, to which a plurality of porcelain or ceramic layers are then applied. The occlusion is examined using an articulator so that the dental prosthetic item fits in the patient's mouth in the best possible way.
The disadvantages of these methods are that, firstly, the contact surfaces are at most as precise as the situation model, which lacks proper dimensional accuracy due to the fact that an impression is made and the resulting model dries out. Secondly, the occlusion can be examined only with the aid of a mechanical articulator, so that flawless functional efficiency of the dental prosthetic item will greatly depend on the skill of the dental technician.
Furthermore, methods are known which no longer require the participation of a dental technician. The dental situation is scanned in the patient's mouth or on an impression by a 3D scanning device. Such scanning is usually performed optically. The scanned data then form the basis for creating a computer-aided design of the dental prosthetic item, which is then fabricated using computer-aided production techniques. Material removing processes, which machine the blanks, either exhibiting or lacking final strength properties, by computer-aided milling and grinding devices, are examples of production processes known in the prior art. Blanks that do not exhibit final strength are brought to their final strength by sintering or infiltration. In addition, it is known that dental prosthetic items can be produced by laser sintering or 3D printing.
The disadvantage of fully automatic production methods is that the dental prosthetic items only partially meet the aesthetic requirements, since a natural tooth has complex optical properties resulting from its multi-layered structure. These properties can be reproduced only to a certain extent when using a single-layered ceramics structure.
Furthermore, methods are known which combine manual production of dental prosthetic items with the automatic production of parts of the dental prosthetic item.
DE 101 31 131 Al discloses a method for the production of a dental prosthetic item comprising individual teeth or groups of teeth, in which intraoral spatial information on the tooth stump or implant holding the prosthetic item is produced, and a model of the jaw or jaw section is prepared with the help of this information. Furthermore, CAD/CAM methods are used to produce a framework, which is adapted to match the dental situation and to which a dental technician manually applies a veneer made of ceramics material.
The disadvantage of the method described above is that the preparation of a model based on digital data is highly elaborate.
It is therefore an object of the present invention to specify methods and devices for the production of dental prosthetic items, enabling economical, accurate, and aesthetically immaculate production of a dental prosthetic item.